Re: [wxperl-users] declarative syntax

[Eric W. <scr...@gm...>]

# from Sergei Steshenko
# on Saturday 17 March 2007 07:16 pm:

>I am not sure I clearly understand what it's about, but why new
> syntax/language to describe hierarchical relationship if Perl already
> supports hierarchical data structures ?

One word:  concisification

>my $children_array_ref =3D # or should it be hash ref ?

No, order matters.

>=A0 [
>=A0 =A0 { # first child

oops, we lost the order now

>=A0 =A0 custom_bit =3D>
>=A0 =A0 =A0 {
=2E..
>=A0 =A0 text_ctrl =3D>
>=A0 =A0 =A0 {
>=A0 =A0 =A0 type =3D> 'ctrl',
>=A0 =A0 =A0 label =3D> "", # I'm not sure about this
>=A0 =A0 =A0 style =3D>
>=A0 =A0 =A0 =A0 {
>=A0 =A0 =A0 =A0 te =3D> MULTILINE|READONLY|DONTWRAP=20
>=A0 =A0 =A0 =A0 # these are meant to be bitwise OR'ed constants=20
>    =A0 =A0 }=20

Yeah, but the te =3D> 'string|string|string' means the style() function=20
can append wxTE_ to the front, so-as to Wx->"wxTE_$thing" it.

>=A0 =A0 =A0 }
>=A0 =A0 },
>
>=A0 =A0 { # second child
>=A0 =A0 ...
>=A0 =A0 }
>=A0 ];

>Whenever I see another language inside Perl, I'm getting really
> nervous - another (possibly incomplete) definition, another (possibly
> buggy) parser ...

Nope, no parser.

>Well, the original example is likely still Perl, but why a subroutine
> where plain hierarchical data structure should suffice ?

The data structure would basically have to be array refs all the way=20
down.  Also, the style() function does some mapping.  The idea was=20
basically to make a mini-language that would add some unverbosity and=20
other conveniencification.

(The Bushism-ated words are jokes.  You should laugh now.  I'm not=20
really going to extendify the language like that.)

A sufficiently expressive data-structure would be good, but it wouldn't=20
be declarative.  The benefit of the declarative bits of code is that=20
their procedural guts can remove the need for ']]]]]]]]]]'(did I get=20
enough brackets in there?)-ish stuff.  I'm still on the fence about=20
many details of implementing either or both.

=2D-Eric
=2D-=20
software:  a hypothetical exercise which happens to compile.
=2D--------------------------------------------------
    http://scratchcomputing.com
=2D--------------------------------------------------